Space-Time Clustering of Testicular Cancer Using Residential Histories Abstract The primary objective of the proposed research project is to generate insights concerning the etiology of testicular cancer by conducting a large, population-wide case-control study in Denmark investigating space- time clustering of cases and controls using residential histories. Testicular cancer is the most common cause of cancer in men aged 15-34 yet relatively little is known about its etiology. The established and presumptive risk factors, taken as a whole, account for only a small proportion of the total cases of testicular cancer, and novel techniques are needed to solve this public health enigma. Our research team has recently developed Q-statistics and Space-Time Information System (STIS) technology that enable space-time cluster analyses. Other methods for analyzing cancer clusters typically ignore residential mobility, and almost exclusively work with static spatial point distributions of place-of-residence at time of diagnosis or time of death. In addition, few spatial techniques adequately account for known risk factors and covariates. Our approach addresses each of these needs by utilizing the residential history of the participants represented as a life-line, and thus evaluates space-time clustering at any moment in the life-course of the residential histories of the cases relative to the residential histories of the controls. In addition, in place of the widely used (but often inappropriate) null hypothesis of spatial randomness, Q-statistics can incorporate each individual's probability of being a case based on his/her risk factors and covariates. This project will apply the innovative Q-statistics and STIS technology to identify spatial clustering of testicular cancer by comparing the residential histories of the cases with those of the controls. The proposed research will select testicular cancer cases (3100) from the nation-wide Danish Cancer Registry (diagnosed in 1994-2003) and controls (3100, matched on age) from the general population. The cases and controls will be linked with residential history information available in the Danish Central Population Registry and Q-statistics will be implemented to examine clustering. Local authorities and registers at the Danish Environmental Protection Agency will be asked to identify possible patterns of environmental contamination surrounding the most significant clusters to generate hypotheses about environmental causes of testicular cancer. Future research will address such environmental hypotheses by collecting biomarkers and modeling environmental contaminants within an epidemiologic framework. This research will, for the first time ever, allow epidemiologists to assess space-time clusters of testicular cancer using detailed residential histories, with the intended purpose of generating fresh hypotheses about potential etiologic factors associated with testicular cancer to be investigated in future studies. Space-Time Clustering of Testicular Cancer Using Residential Histories Relevance The scientific innovations from this research are expected to dramatically improve our understanding of testicular cancer, the most common type of cancer in men aged 15-34. This research will enable environmental and spatial epidemiologists to investigate spatial clusters of testicular cancer by comparing residential histories of cases with residential histories of controls, with the intended purpose of generating fresh hypotheses concerning the etiology of testicular cancer. [unreadable] [unreadable] [unreadable] [unreadable]